Iron deposits and multiple sclerosis.

A recent publication described autopsy samples from five brains in which positive staining for iron was observed as surrounding demyelinated plaques. Because this has not been previously reported, autopsy material from 13 patients who were being followed up at the Multiple Sclerosis (MS) Clinic, University Hospital, The University of Western Ontario, London, Ontario, was reviewed. A total of 32 paraffin-embedded blocks containing demyelinated plaques of varying age were sectioned and stained using a standard acid ferrocyanide technique (Peris' test) for iron. Microscopic examination failed to detect the presence of significant positive staining either within or surrounding the areas of demyelination. Positive histochemical staining for iron identifies hemosiderin, the presence of which suggests either iron overload or remote hemorrhage. Support for these two processes in the pathogenesis of MS could not be provided from our material.